Yeah, you definitely need the `Content-Type: application/json` header when curl sending json. The server won’t know it’s JSON without it!
Also, make sure your JSON is properly escaped. Try wrapping it in single quotes and escaping double quotes inside, like:
```bash
curl -X POST http://example.com/api -H "Content-Type: application/json" -d '{\"key\":\"value\"}'
```
If that doesn’t work, maybe test your JSON in a validator like [jsonlint.com](https://jsonlint.com) to spot syntax errors.
Also, make sure your JSON is properly escaped. Try wrapping it in single quotes and escaping double quotes inside, like:
```bash
curl -X POST http://example.com/api -H "Content-Type: application/json" -d '{\"key\":\"value\"}'
```
If that doesn’t work, maybe test your JSON in a validator like [jsonlint.com](https://jsonlint.com) to spot syntax errors.